User`s manual

Using a Multiplexer
with the Multimeter
Figure C-8 shows an example timing sequence between closing a multiplexer
channel and triggering the multimeter.
Comments
• The registers used are:
– multiplexer Status Register (base + 0
16
)
– multimeter Status Register (base + 04
16
)
– multiplexer/multimeter Command Register (base + 08
16
)
• The multiplexer Status Register is monitored to determine when a
channel can be closed (or opened), and when a channel has finished
closing (or opening).
• Multimeter status bit 0 is monitored to determine when a trigger
opcode can be written to the Command Register (the flowchart
assumes the multimeter is already configured).
• Multimeter status bit 5 is monitored to determine when the
analog-to-digital (A/D) conversion is in progress, and thus, when to
advance the channel. This enables each channel to be measured before
the readings are read from the buffer.
The channel can also be advanced by monitoring bit 4 (Data Ready).
However, before measuring the next channel, readings from the
previous channel must be read from the buffer in order to clear the bit.
• Autozero is often turned on in order to detect when bit 5 is active
(see “The Status Register” on page 206).
Figure C-8. Using a Multiplexer with the Multimeter
216 HP E1326B/E1411B Multimeter Register-Based Programming Appendix C